We spend half our lives looking at screens, so you might as well make sure the one you stare at is good, right? At present there are two main, broad kinds of display seen across monitors, TVs, mobile phones, cameras and pretty much everything else.

In one corner sits LCD, by far the most common type of display in all kinds of tech. If you see a TV described as ‘LED’ it's actually an LCD display with a backlight that's made of LEDs rather than another kind of light source.

OLED is completely different, though, used in phones like the Samsung Galaxy S5 and TVs like the LG 55EC930V.

Some people say OLED is the future, but is it really that much better than a good LED LCD display? We’re going to look into how these display techs differ, what they’re good for and how they work.

In a nutshell, how are they different?

To distil the differences between these technologies into the most concise little nugget, LED LCD displays use a backlight to illuminate their pixels while OLED’s pixels actually produce their own light.

You might hear OLED’s pixels called ‘emissive’.

What this means is that the brightness of an OLED display can be controlled pixel-by-pixel. This sort of control just isn’t possible with an LED LCD.

In cheaper TVs and LCD-screen phones (that’ll be most of them), LED LCD screens use LED backlights that actually sit to the side of the display, not right behind it. The light from these LEDs is then fired through a matrix that feeds it through the red green and blue pixels and into our eyes.

So with one of these sorts of screens, the control over the level of brightness across the display is limited. Take an LCD display into a darkened room and you’ll notice that parts of an image aren’t perfectly black, because you can still see the backlight showing through.

This is also a good time to explain contrast. Particularly in TVs and monitors, you’ll often see a contrast ratio quoted. This tells you how much brighter a display’s whites are compared to its blacks, and a decent LCD screen might have a contrast ratio of 1,000:1.

The whites are a thousand times brighter than the blacks. 

OLED vs LED LCD: OLED Contrast In an OLED display, as a pure black screen should not emit any light at all, you get an infinite contrast ratio. No matter how many times you multiply nothing, you end up with zilch.

When you see a ‘dynamic’ contrast ratio figure, which will likely be much higher, that’s when an LCD’s measurement is taken allowing the backlight to be dimmed while checking out the light emitted from a black screen. It’s not really a good indication of the sort of contrast you’ll see in, say, movies because there the variance in screen brightness is much less predictable. You can't dim the backlight when another part of the screen needs a good level of luminance.

Trying too hard to alter backlight levels to suit can cause obvious and jarring ligh level changes too.

There are LED LCD displays that have a good crack at replicating the sort of contrast you get with OLED, though, called direct LED displays. Here, the LEDs sit right behind the LCD panel rather than to the side of it, giving a screen greater control over how bright certain areas of a screen are.

You’ll find this tech in some higher-end TVs. However, how effective it varies.

Direct LED-lit TVs still don’t have pixel-level control over light levels like OLED. Instead, a display has ‘zones’ or groups of LEDs than can be dimmed. It can be extremely useful for doing things like blacking-out the bars you see when watching a 21:9 cinema aspect movie on a 16:9 TV, but generally isn’t as good at dealing with more complicated tasks.

For example, if there was an image of someone’s brightly-lit face on top of a completely black background, you might see a halo of light around parts of the face because the backlight zones didn’t quite match up with what’s on screen. If you’ve read some of our TV reviews, you may have heard our TV expert John Archer talk about this sort of halo’ing.

Of course, TV makers like Sony are getting better at this every year.

Can LCD match OLED? However, we had a chat with professional ISF television calibrator Vincent Teoh who told us, “LED LCDs will never match OLED in black level,” but also says that LCD “already surpasses [OLED] in peak brightness.”

For watching content in dark rooms, an OLED display is the best solution you can currently get, and in the TV space that has become all the more important now that plasma TVs are not made any more. Plasma displays used to be the go-to technology to get better contrast than LCDs, but every company that used to make such sets ceased after people, well, stopped buying them.

OLEDs displays are great for screen enthusiasts, and not just in TVs. The OLED used on the Samsung Galaxy Note 4 probably has the best phone screen ever made: DisplayMate said it “has again raised the bar for top display performance up by another notch.”

SEE ALSO: Curved TVs: The Pros and Cons

Samsung is the main supporter of OLED phones, though — while Nokia Lumia and Motorola have occasionally used OLED screens, Sony, Apple and LG all predominantly use LCD-type displays in their phones.

LCD continues to dominate TVs too. Teoh says LCD will “remain the dominant TV tech until OLED achieves price parity size-for-size and spec-for-spec, which won't happen for at least 5 years — if OLED even survives that long.”

Where are all the OLEDs? So if OLED is so good, where are all the OLED TVs?

It turns out they are extremely difficult to produce. Only two companies to date have released full-size, commercially-available TVs, Samsung and LG. And only one continues: LG.

Samsung’s OLED was called the KE55S9C, and it sold for £7,000. For that price you’d expect perfection, but there was a concern about the blue LEDs used in the set — they last for less time than the green and red ones. It’s still enough for years of operation, but given the price it was a worry.

LG gets over this issue in its OLED TVs by using white LEDs, and colour filters over the top of them. It’s a little more LCD-like in this respect.

The company is doing great work in trying to make OLED TVs more mainstream, and while there’s a way to go before OLED models are anywhere close to the sort of prices non-enthusiasts can afford, LG is ploughing away where other TV makers steer clear.

“2015 will be a key year for OLED TV as we will really demonstrate our commitment to OLED technology by investing over $600m into production sites across the world that will take production to 1m units,” LG Product & Range Planning Manager Robert Taylor told us.

“The benefits of this extra production will result in greater economies of scale which will enable us to produce not only a wider array and range of OLED TV products but also in greater volume, resulting in better cost prices and reduced production costs. With these savings we will be able to make OLED TV’s more effectively and even look to create more entry level models.”

That last part is important: entry-level models. The cheapest OLED currently available is the LG 55EC930V, which costs £2,499.99. That’s not crazy money like the earlier-generation £8k TVs, but the price floor needs to be lowered a bit more before OLED TVs can take off in the way we want them to.

What are the benefits of LCD?

Lower cost is one of the main benefits of LCD displays, across all fields. You’ll find high-quality LCD screens in devices that cost (relatively-speaking) peanuts, such as the IPS panel of the Motorola Moto E, a phone that costs well under £100, if you shop around. The affordability of LCD is what has made 4Ks so affordable so quickly: you can get a 4K set for well under £500 now, while the cheapest 4K OLED is the 65-inch, £6,500 LG 65EC970V.

LCD screens can often look sharper than OLED displays of the same resolution too. It’s all down to the tactics display producers use to deal with OLED’s quirks.

The problem is that not only do different colour LEDs have different lifespans, they also have different levels of light output. So while LCD screens can use incredibly regular patterns of red, green and blue sub-pixels, OLED displays generally have to be a bit more… dynamic.

For example, in the Galaxy Note 4, instead of having pixels with three regular sub-pixels, there are red-green-blue-green little dots that effectively form two pixels. They’re not the same shape either: the reds and blues and diamond-shaped while the greens are smaller ovals.

This is called a PenTile arrangement, and makes less pixel-packed OLED displays look a bit fizzy. The effect has largely disappeared in recent phones thanks to the sheer resolution on offer, and LG’s OLED TVs do not need to use such techniques as they use a colour filter rather than coloured LEDs.

But OLEDs just aren't as easy to work with as LCDs it seems.

OLED vs LED LCD: Viewing Angle

OLED displays tend to have near-perfect viewing angles, although they will often take on a slightly different hue when viewed from an angle. The Galaxy Note 4, for example, goes a bit blue-ish.

In LCDs, angles viewing varies hugely depending on the display technology used. And there are lots of different kinds of LCD panel.

Perhaps the most basic is twisted nematic (TN). This is the kind used in budget computer monitors, cheaper laptops and some very low-cost phones. It offers very poor angled viewing. If you’ve ever noticed that your computer screen looks all shadowy from the wrong angle it’s because it has a twisted nematic panel.

Thankfully a lot LCD devices use IPS panels these days. This stands for in-plane switching and it generally provides much better colour performance and dramatically improved angled viewing.

IPS is used in the vast majority of smartphones and tablets, plenty of computer monitors and lots of TVs. It’s important to note that IPS and LED LCD aren’t mutually exclusive, it’s just another bit of jargon to tack on. Display tech engineers sure seem to have a thing for acronyms.

OLED vs LED LCD: Colour The latest LCD screens can produce fantastic natural-looking colours. However, just as with the viewing angle, it depends on the specific technology used.

IPS and VA (vertical alignment) screens can provide great colour accuracy when properly calibrated — the iPhone 6 is a great example of a phone with top colour — but TN screens can often look weak or washed-out.

OLED screens have even greater colour potential than the best LCDs, but the problem here is reining them in. These screens are capable of reproducing more of the natural colour spectrum than is actually covered by the standards used in film and software production, but that means if they’re not properly calibrated colours can look overcooked.

You’ll see this quite commonly in OLED phones, but OLED TVs — being enthusiast products — tend to have fantastic colour reproductio

What is the future for LCD and LED?

Display makers are doing their best to tweak and improve the various limitations of LCD, though. While OLED’s job over the next few years is to become more affordable and just get out there a bit more, we’re seeing more distinct developments in LCD town.

Perhaps the most catchy is the quantum dot. It is a new way to approach the LCD’s backlight. Rather than using white LEDs, a quantum dot screen uses blue LEDs and these ‘quantum dots’ of various sizes, which convert the light into different colours by altering its wavelength.

Our TV calibrator buddy Vincent Teoh had a few words to say on quantum dots too:

“It's not a stop gap – it's crucial to help LED LCD achieve a wide enough colour gamut to satisfy current UHD standards. For normal HD stuff, most consumers probably won't appreciate (or care) about quantum dot vs non-quantum dot displays.”

Some of Amazon’s Kindle Fire HD tablets already use quantum dot tech and at CES 2015 TVs from LG, Samsung and Sony were all seen using the trendy nano particles. While LCD is never going to match OLED for black level and contrast, any limits to colour reproduction are being whittled away.

Both kinds of display are also on the road to being ready for the next big standard in TV, too: HDR. This stands for high dynamic range and involves bringing out more detail in shadow areas, and highlights. You may have seen the mode in your phone's camera, and soon we'll be watching HDR movies. But to relay HDR content without looking washed-out will require a whole lot of contrast. OLED whites will get brighter, and with any luck LCD backs will get darker.

Whether you side with LCD or OLED, the future is certainly going to be interesting.